Schools Secretary Ed Balls was today forced into a humiliating climbdown over controversial plans to make sex education compulsory for teenagers.

Mr Balls was forced to drop a string of proposals from his flagship Children, Schools and Families bill following fierce opposition from the Tories.

The measures to force all teenagers from the age of 15 upwards to receive sex education has been opposed by parenting and religious groups.

Ed Balls and Yvette Cooper arrive at 10 Downing Street yesterday. Today Mr Balls had to back down on his sex education plans

The Schools Secretary has also had to ditch plans to make parents sign so-called 'behaviour' contracts with schools and to force parents who educate their children at home to register with local councils.

A guarantee of one-to-one tuition for pupils who fall behind in English and maths has also been dropped along with school report cards - which would have graded institutions on a range of criteria such as exam performance and pupil behaviour.

Mr Balls today confirmed that key parts of his schools Bill had been stripped out entirely so that he could push through the legislation before Parliament rises - a period known as the 'wash-up'.

Under the plans, all teenagers from the age of 15 would have received lessons in subjects such as how to bring up children, sexual activity, contraception, abortion and adoption from next year.

But experts warned that the sex classes could lead to teenage pregnancy being seen as increasingly acceptable.

The Tories claimed the climbdown was another victory following major Government u-turns over cider duty hikes, broadband taxes and furnished holiday lettings.

A Conservative spokesman said: 'We supported having better sex education but the Government insisted on removing parents' rights to withdraw their children from classes they thought damaging - and we think parents must have such a right.

'This Bill would have meant a great new wave of bureaucracy swamping schools and it is good news that it has collapsed. Teachers will breathe a sigh of relief.'

Mr Balls responded furiously by removing all the Government's plans for all pupils to receive so-called 'lifestyle' lessons in state schools from the age of 5.

In a letter to his Tory counterpart Michael Gove, Mr Balls said: 'Our reforms would ensure that by reducing the age of parental opt-out to 15, all children receive at least one year of compulsory sex and relationship education (SRE).

'This is a very significant setback, which will deny many young people proper and balanced sex and relationships education.'

But Norman Wells, Director of the Family Education Trust, said: 'Parents have been increasingly sidelined and effectively told they must bring up their children by government diktat.

'It is time for politicians from all parties to start showing parents more respect and to recognise that the family is a private institution, not an arm of the state.'

Margaret Morrisey, from campaign group Parent Outloud, added.'The majority of parents prefer to speak to their children about sex and relationships in their own time, in their own way and in their own language. They would have lost that right.'

But Lisa Power, from the Terrence Higgins Trust said: 'It's a disgraceful betrayal of the next generation. This isn't just about sex - it's about relationships, it's about bullying, it's about a whole raft of things.'